Pickproof cylinder lock

ABSTRACT

A pickproof cylinder lock has a plurality of spring-tensioned pins slidably mounted in the lock cylinder, with each pin carrying a ball which is raised or lowered with the pin. The balls are arranged in a chain which, in the normal position of the pins, is of insufficient length to open the lock. When the proper key is inserted, the balls are brought into horizontal alignment, forming a straight chain of greater length which pivots a lever to bring the lock to open position.

United States Patent 11 1 1111 3,928,993

Epstein 1 Dec. 30, 1975 1 PICKPROOF CYLINDER LOCK 3,410,123 11/1968 Jacobi.... 70/364 R [75] lnventor: Norman Epstein, Carmel, N.Y. 3599'455 8/l971 Pllvet /363 73 N L k C M' h N.Y.

[ l fslgnee ("man 0c 0 d opac Primary ExaminerRobert L. Wolfe l l Flled? g- 1974 Attorney, Agent, or Firm-Edward F. Levy Appl. No.: 501,808

Related U.S. Application Data [63] Continuation of Scr. No. 388,428, Aug. I5, 1973, [57] ABSTRACT abandoned' A pickproof cylinder lock has a plurality of springtensioned pins slidably mounted in the lock cylinder, [52] U.S. Cl. 70/419, 70/364 A, 77047137896 with each p y g a ban which is raised or 2 ered with the pin. The balls are arranged in a chain [51 1 CL Z J? which, in the normal position of the pins, is of insuffi- [581 Field of Search 70/362 364 364 A 379 cient length to open the lock. When the proper key 1s 76/380 inserted, the balls are brought into horizontal alignment, forming a straight chain of greater length which [56} References Cited pivots a lever to bring the lock to open position.

UNITED STATES PATENTS 13 Claims, 8 Drawing Figures 570,032 10/1896 Luebbers 70/386 X 3 g 7o 72 1 Q 5 I J l/ \I 32 1a 26 less US. Patent Dec.30, 1975 SheetlofZ 3,928,993

PICKPROOF CYLINDER LOCK This application is a continuation of my co-pending U.S. Pat. application Ser. No. 388,428 filed Aug. 15, 1973 and now abandoned and entitled Pick-proof Cylinder Lock.

The present invention relates to cylinder type locks, and in particular, to a lock which is pickproof. The lock operates on the novel principle of utilizing thetumbler pins to bring a corresponding number of elements, such as balls, into a straightline chain which transmits a force longitudinally through the lock to produce the opening action.

In conventional cylinder locks a plug or cylinder is rotatably mounted in a housing, and the lock is opened by turning the cylinder within the housing after the proper key has been inserted through the keyhole. The cylinder is normally restrained from turning movement by a number of pin tumblers of different lengths and comprising upper and lower segments which are springbiased downwardly into the keyway slot. When the proper key is inserted in the lock, each of the pin tumblers is elevated to a selected position in which the junctures of the upper and lower segments register with the outer circumference of the cylinder. Thus, by turning the inserted key, the cylinder may be rotated, carrying with it the lower pin sections and leaving the upper sections in the lock housing.

In the conventional locks described above, the lock can be readily picked by an experienced person since a torque force can be applied to the cylinder while a picking tool is used to elevate each of the pin tumblers. The torque force applied to the cylinder effects a fric tional bearing upon the pin tumblers which can be felt by the person picking the lock. Thus, as the pin tumblers are raised, the person can ascertain by feel a slight movement of the cylinder when the pin reaches its release position.

It is an object of the present invention to provide a cylinder lock in which there is no frictional bearing provided between any of the lock parts during the opening operation so that a person tampering with the lock can feel no movement therein, and thus the lock is pickproof.

Another object of the invention is to provide a pickproof lock which operates upon a novel principle different from that of conventional locks. Locks in use today are locked and unlocked by parallel mechanical elements such as pins or levers, each performing an identical function to individually prevent a cylinder from rotating or a bolt from moving unless all the elements are properly individually positioned. In the lock of the present invention, the locking and unlocking elements do not operate independently but rather operate serially to cooperate with each other to provide an opening movement only when all of the elements are properly positioned.

Still another object of the present invention is to provide a pickproof lock in which insertion of the proper key results in moving a plurality of actuating elements, such as small balls, into a straight-line chain through which a force is transmitted to cause the lock to open. The actuating elementsare raised and lowered by the tumbler pins of the lock, but are movable laterally relative thereto so that the longitudinal, lock-opening force exerted by the actuating elements cannot be felt through the pins.

A further object of the invention is the provision of a pickproof lock of the character described which contains a few simple parts and which is economical in manufacture.

In accordance with the invention, there is provided a pickproof lock comprising a cylinder rotatably mounted in a housing, an actuating member movably mounted within the cylinder and normally urged to a first position in which the lock is closed, a plurality of spring-biased pins slidably mounted in the cylinder, and a lock-release element carried by each of said pins and movable therewith. The pins have a normal lock-closed position in which the lock-release elements are maintained at different levels. The pins are movable, upon insertion of a proper key in the lock, to a position in which the lock-release elements are located in a straight line to form a linear chain of elements for transmitting a lock-opening force through said cylinder to said actuating member, whereby to move the latter to a second, lock-opening position.

In a preferred embodiment of the lock, the lockrelease elements are in the nature of small balls which form a chain between the actuating member and a fixed portion of the cylinder. When the balls are out of horizontal alignment, the distancefrom one end of the chain to the other is insufficient to move the actuating member. When the balls are brought into horizontal alignment to form a straight-line chain, the distance from one end of the chain to the other is sufficient to provide the lock-opening force which moves the actuating member to its lock-opening position.

Additional objects and advantages of the invention will become apparent during the course of the following specification, when taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of an assembled lock made in accordance with the invention;

FIG. 2 is an exploded perspective view of the cylinder and associated parts of the lockv shown in FIG. 1;

FIG. 3 is an enlarged longitudinal section taken along line 33 of FIG. 1;

FIG. 4 is a schematic view showing the positions of the lock elements when the proper key is inserted and the lock is in open condition;

FIG. 5 is a schematic view similar to FIG. 4, but showing the lock elementsin the closed condition of the lock;

FIG. 6 is an enlarged transverse section taken along line 6-6 of FIG. 1;

FIG. 7 is an enlarged top plan'view of a portion of the lock cylinder showing the manner in which a slot and bores are formed therein; and

FIG. 8 is a longitudinal section through an alternative embodiment of lock made in accordance with the invention.

Referring in detail to the drawings, there is shown in FIGS. 1 and 2 a preferred embodiment of lock 10 made in accordance with the present invention. The lock 10 comprises a hollow cylindrical casing 12 within which is rotatably mounted the lock cylinder 14.

The cylinder 14 has in its front wall a keyhole vl6 communicating with the longitudinal keyway'slot 18 into which a key 19 may be inserted. In contrast to conventional tumbler locks, the keyhole 16 and slot 18 are not centrally located in the cylinder 14 but rather are offset from the center and are located adjacent the circumferential edge of the cylinder 14. In the locked condition of lock 10, shown in FIGS. 1 and 2, the keyhole 16 is located adjacent the bottom edge of cylinder 14.

In the circumferential surface of cylinder 14, diametrically opposed to the edge portion containing keyhole 16, there is formed a longitudinal slot 20 which extends somewhat less than the entire length of cylinder 14. The slot 20 also extends downwardly through the body of cylinder 14 to the keyway slot 18.

A row of circular bores 22 is drilled along one longitudinal edge of slot 20, and a second row of circular bores 24 are drilled along the opposite longitudinal edge of slot 20. These bores 22 and 24 extend diametrically through the interior of cylinder 14 and communicate with the keyway slot 18.

In each of the bores 22 and 24, a pin 26 is slidably located, the pins being urged downwardly to the lower ends of the bores by respective coil springs 28. The lower ends of the springs 28 are connected to the respective pins 26, and the upper ends thereof are seated against a casting 29 which is inserted into the upper ends of the bores 22 and 24 and the slot 20 to close off the latter.

The pins 26 are each of identical construction, although their lengths are varied. Each pin 26 has a cylindrical body portion 30 having a rounded or tapered bottom end 32. Upstanding from the body portion 30 is a post 34 of narrow diameter, terminating in an integral flat disc 36. The disc 36 and the flat upper surface of each pin body portion 30 provide a space for receiving and mounting a small metal ball 40 which is the prime element in the locking and unlocking of the lock. Each pin 26 mounts one of the balls 40, and in each instance the disc 36 partially overlaps the ball in the manner shown in FIG. 6. In the mounting of the pins 26 and balls 40, the balls are oriented so that they all face inwardly of the slot 20. In this mounted position, all of the balls 40 are in a straight line aligned with the longitudinal axis of the cylinder 14. As shown in FIG. 7, the slot 20 is shaped to hold the balls 40 in longitudinal alignment but to allow a slight degree of transverse movement of the balls relative to each other, in a manner to be presently explained.

As previously indicated, the pins 26 are of different lengths, this being accomplished by selectively varying the lengths of the pin body portions 30, as best shown in FIGS. 4 and S, the posts 34 and discs 36 all being of identical dimension. When no key is inserted in the lock, the pins 26 are urged downwardly through their respective bores until their free, tapered ends 32 are located at the same level within the keyway slot 18, as shown in FIG. 3. In this position of the pins, the balls 40, while in longitudinal alignment, are not located at the same horizontal level.

Also mounted within the cylinder 14 is an actuating lever 42 having a depending arm 44. The lever 42 is pivotally mounted by a ball 46 which serves as a pivot therefor. A wire spring 48 normally urges the lever 42 to a position in which its arm 44 extends vertically downward. One end of the spring 48 is received within a small bore 50 in the lever 42, while the other end of the spring is connected to a fixed portion 52 of cylinder 14.

A circular plate 54 is press-fit within the rear of the hollow casing 14 to serve as the rear wall thereof. The plate 54 has a central circular bore 56 which communicates at its front end with a circular bore 58 of greater diameter to form a shoulder 60. The plate rotatably mounts a coupling member 62 comprising a cylindrical 4 shaft 64 at the forward portion of which is a circular peripheral flange 66. The portion of shaft 64 which projects forwardly of the flange 66 is cut to provide a diametrically-extending slot 68 (FIG. 2). This slot 68 is sized to receive the depending arm 44 of lever 42.

In the mounted position of the coupling member 62 within the circular plate 54, as shown in FIG. 3, the shaft 64 extends rotatably through the bore 56, and the flange 66 is located within the larger bore 58, resting against shoulder 60. The forward end portion of the shaft 64 projects forwardly from the plate 54 with the slot 68 in alignment with the arm 44 of lever 42 and located to receive said arm when the lever 42 is pivoted toward plate 54. The rear portion of shaft 64 projects rearwardly from the plate 54 and is connected, externally of the lock 10, to a member 70 forming part of an external latch mechanism, such as a door latch.

FIG. 3 shows the lock 10 in its locked condition in which it is incapable of opening the external latch mechanism unless the proper key is inserted. This locked condition is actually a dormant, inoperative condition in which the pins 26 extend freely within the keyway slot 18 and are wholly located within the cylinder. The pins 26 hold the respective balls 40 at different horizontal levels, as shown in FIGS. 3 and 5, so that the horizontal diameters of the balls are not in alignment. The ball 40a at the forward end of the row of balls 40 is in engagement with a fixed internal wall portion 72 of cylinder 14, while the ball 40b at the rear end of the row of balls is in engagement with the lever arm 44. Since the balls 40 are not in registry, that is not in horizontal alignment, the balls engage each other at various circumferential points and not at the points of maximum diameter, so that the distance between the first ball 40a and the last ball 40b is relatively short. The lever 42 is thus maintained by spring 48 in an inoperative position, with its arm 44 depending vertically, as shown in FIG. 4, the arm being remote from the coupling member 62.

Since, in this locked condition, the lever 42 is out of engagement with the coupling member 62, the lock 10 is disengaged from the latching mechanism of the door or other member in which the lock is mounted. In this embodiment, the cylinder can be freely rotated (as by insertion of a tool or an improper key), without releasing the latching mechanism. It will thus be appreciated that the lock 10 operates under a different principle from conventional locks in which the pins block turning and are elevated and lowered to provide a shear line permitting rotation of the cylinder. In the lock 10 herein, the pins themselves produce no blocking or unblocking action, but function merely to raise and lower the respective balls 40, the balls cooperating to produce a longitudinal force which provides the unlocking action in a manner to be presently described.

It is to be understood that since the bores 22 and 24 are arranged in the cylinder 14 in two spaced longitudinal rows, the pins 26 inserted in these bores are likewise arranged in two corresponding rows. In the illustrated embodiment, as shown in FIG. 2, provision is made for four bores 22 (and thus four pins) in one row,

cross-section having a pair of parallel shanks 74 and 76 connected by a cross-piece 78. Each of the shanks 74 and 76 is selectively ground to provide the usual slots and ridges, or dwells and elevations which operate to raise the pins to various heights. The keyhole 16 is correspondingly shaped, having a pair of spaced slot sections 80 and 82 connected by a cross-slot 84.

When the key 19 is inserted in the keyhole 16 and slid through the keyway slot 18, the dwells and elevations on the key shanks 74 and 76 engage the tapered tips 32 of the respective pins 26 of each row, and raise each pin 26 to the proper level, balls 40 being carried upwardly with the pins. FIG. 4 shows schematically the operative or unlocked condition of the lock 10, in which the proper key 19 has been inserted and the elevated pins 26 have brought the balls 40 into registry elevating the pins to bring some, but not all, of the balls with each other, that is, into horizontal alignment. To

reach this aligned position, the balls 40 each move a short distance laterally, such lateral movememt being permitted because of the loose mounting of each ball between the disc 36 and top surface of the body portion of the respective pin 26. In the horizontally aligned position of the balls 40, the first ball a is still in engagement with the wall 72 of cylinder 14, but each ball engages the adjacent ball at a circumferential point in line with the diameter of the ball. The distance between the forward edge of the first ball 40a and the rear edge of the last ball 40b is now considerably greater than the distance between these balls in the locked, inoperative position of FIG. 5. The balls 40, aided by the downward pressure of a spring 28 upon each ball, now form a solid, linear chain of increased length bearing against the cylinder wall 72 at one end and against the lever arm 44 at the other end.

As the chain of balls 40 increases in length, it exerts a force in a direction parallel to the longitudinal axis of the cylinder 14, against the lever arm 44, causing the lever 42 to pivot and elevate the arm 44 until the latter enters the slot 68 in the coupling member 62. The cylinder 14 is now rigidly connected to the latch member 70 through the coupling member 62, and the lock is now in the release or unlocking position. When the key 19 is turned to rotate the cylinder 14, engagement of the lever arm 44 with the coupling member slot 68 causes the coupling member 62 to rotate with cylinder 14. Such rotation of the coupling member 62 also turns the latch member 70, causing the latter to operate in the usual manner to release the latch mechanism.

FIG. 7 shows a top view of a portion of the slot 20 and bores 22 and 24, and illustrates the manner in which slot 20 is milled or cast to permit limited lateral movement of each of the balls 40. The slot 20 is formed to provide a triangular projection or lip 86 at one side of each of the bores 22, and a similar triangular projection or lip 88 at the opposite side of each of the bores 24. The distance between any lip 86 and the adjacent lip 88 is slightly greater than the diameter of a ball 40. When a ball 40 is mounted on a pin 26 inserted in one of the bores 22 or 24, it is free to move laterally in either direction relative to its pin, but the lips 86 and 88 act as end stops to limit the movement of the ball to a short distance, thereby preventing the ball from rolling free of its pin. In one operative embodiment, each ball is 0.093 inches in diameter, and is permitted 0.035 inches of movement between a pair of lips 86 and 88.

The aforementioned operation of the lock 10 is such as to make the lock virtually pickproof. If the wrong key is inserted into the lock, and the key is capable of 40 into alignment, the balls will move laterally, but will not form a'chain of sufficient length to turn lever 42 to its operative position.

In conventional locks, because the pins are used to block movement of the lock cylinder, it is possible to pick the lock by use of a picking tool while applying torque to the cylinder. Tension on the pins can be felt through the picking tool so that the pins by feel or feed-back can be individually raised to the proper unlocking position. In the lock 10 of the present invention, the pins 26 are raised merely to bring the balls 40 into an aligned chain, and since the balls are laterally movable relative to the pins, there is no tension exerted at any time on the pins 26. Consequently, even if a picking tool is employed, there is no tension on any of the pins to be detected through the tool. It will also be appreciated that, even through the last ball 40b of the chain of balls is in engagement with lever 42, the lock cannot be opened by use of a. suitable picking tool to elevate the pin carrying the last ball 40b. If this pin is elevated alone, the ball 40b will not pivot the lever 42, but, since no chain of aligned balls is behind it, will simply roll away from the lever.

FIG. 8 illustrates an alternate embodiment of lock 90 in which a horizontally-aligned chain of balls 40, carried by pins 26, is again utilized to exert a force longitudinally along the lock for opening the same. In this embodiment, however, the cylinder 14 is not freely rotatable, but is normally secured to the lock 90 in locked condition, and the balls 40 operate to release the cylinder from the casing.

In the lock 90, the cylinder 14 is secured to a circular end plate 92 to which is secured an external latch member 94. When the cylinder 14 is rotated, it rotates the end plate 92, which in turn moves the latch member 94 to open the external latch mechanism. The cylinder 14 is,.however, locked to the hollow casing 12 .bya lever 96 mounted by pivot 98 within the cylinder 14. The lever has a projecting extension portion 100 which, in the operative-depending position of the lever shown in FIG. 8, extends through a slot 102 in the cylinder and into a registeringslot 104 in the casing 12. A spring 105 urges the lever 96 to the operativelocking positionshown, in which its extension portion 100 projects through the slot 102 and into slot 104 to couple the cylinder 14 to the casing 12 and block rotation of the cylinder.

The balls 40 carried by the pins 26,.are arranged in a row but at different horizontal levels, in the manner previously described, so that when no key is inserted in lock 90, the distance between the first and last balls in the row is insufficient to pivot the lever 96. When the proper key is inserted in the lock, the balls 40 are raised by the pins 26 into a horizontally-aligned chain of increased length. The end ball 40b in engagement with lever arm 106 turns the lever 96 forwardly about pivot numerous additions, changes and omissions may be made in such embodiments without departing from the spirit and scope of the invention.

What is claimed is:

1. A locking mechanism characterized by:

a body having a longitudinally extending key slot therein;

a lock-operating member mounted in the body for movement from a normal position toward a second position which it must occupy before the lock can be released;

a plurality of key-actuatable members movably mounted within the body;

means urging said key-actuatable members toward positions at which portions thereof are engageable by a key inserted into the key slot, and from which positions said key-actuatable members are movable to predetermine unlocking positions by a proper key in said slot;

and lock-release means connected to said key-actuatable members to move therewith, through which key produced motion of said key-actuatable members to their unlocking positions is translated into force'on said lock-operating member to effect motion thereof to its said second position;

said lock-release means comprising a lock-release element carried by each of said key-actuatable members, said key-actuatable members having a normal lock-closed position in which said lockrelease elements are maintained out of operative association with each other, said key-actuatable members in their unlocking positions retaining said lock-release elements in operative engagement with each other, with each element exerting a force upon the adjacent elements and said force being transmitted to said lock-operating member in a direction to move the latter to its said second position- 2. A locking mechanism according to claim 1 in which said key-actuatable members comprise springbiased pins slidably mounted in said body and in which said lock-release elements comprise balls, said pins having elongated pin bodies of various lengths, an upstanding post of reduced diameter on each pin body, and a disc at the free end of each post, said disc and the upper surface of said pin body providing a space in which a ball is received, each ball being movable longitudinally of the body relative to the pin upon which it is mounted, said balls, in the lock-open position of said pins, forming a linear link for transmitting said force to said lock-operating member.

3. A pick-proof lock comprising:

a cylinder rotatably mounted in a housing;

an actuating member movably mounted within said cylinder;

means urging said actuating member to a first position in which said lock is closed;

a plurality of spring-biased pins slidably mounted in said cylinder; and

a lock-release element carried by each of said pins and movable therewith; said pins having a normal lock-closed position in which said lock-release elements are maintained at different levels, I

said pins being movable, upon insertion of a proper key in said lock, to a lock-open position in which said lock-release elements are located in interengaged relationship to form a linear chain of elements for transmitting a lock-opening force through said cylinder to said actuating member, whereby to move the latter to a second, lock-opening position.

4. A pick-proof lock according to claim 3 in which said lock-release elements are spherical balls and in which said pins have elongated pin bodies of various lengths, an upstanding post of reduced diameter on each pin body, and a disc at the free end of each post, said disc and the upper surfaace of said pin body providing a space in which a ball is received, each ball being laterally movable relative to the pin upon which it is mounted.

5. A pick-proof lock according to claim 4 in which said balls are arranged in a chain between said actuating member and a fixed position of said cylinder, said balls being at different levels in the lock-closed position of said pins and the distance between the balls at each end of said chain being insufficient to move said actuating member, said balls being brought into registry in the lock-open position of said pins to form a straight-line chain in which each ball engages the adjacent balls at a point along its diameter to provide a linear chain of greater length, the distance from one end of said linear chain to the other end being sufficient to provide said lock-opening force against said actuating member for moving the latter to its lock-opening position.

6. A pick-proof lock according to claim 3 in which said actuating member is a lever pivotally mounted within said cylinder.

7. A pick-proof lock according to claim 5 in which said actuating member is a lever pivotally mounted within said cylinder.

8. A pick-proof lock according to claim 7 in which said cylinder is freely rotatable in said casing in the locked condition of said lock, and in which a coupling member is journalled in said casing and connected to latch mechanism exteriorly of said lock, said lever having an arm located remote from said coupling member in the first position of said lever, said arm engaging and gripping said coupling member in the second position of said lever, whereby said coupling member is rotatable with said casing to actuate said latch mechanism.

9. A pick-proof lock according to claim 8 in which said coupling member includes a cylindrical shaft journalled in an end wall of said casing, said shaft having an end slot sized to receive said arm of said lever.

10. A pick-proof lock according to claim 7 in which said lever has an extension portion projecting from said cylinder and engaging said casing for coupling said cylinder to said casing and restraining rotation of said cylinder, said extension portion moving out of engagement with said casing when said lever is brought to its lock-opening position to release said cylinder for rotational movement within said casing.

11. A pick-proof lock according to claim 4 in which said pins are arranged in two parallel rows, and in which said balls are mounted on said pins in a direction facing the opposite row, with said balls in alignment along the longitudinal axis of said cylinder.

12. A pick-proof lock according to claim 11 in which said cylinder has a double keyhole and keyway in alignment with the respective rows of pins.

13. A locking mechanism according to claim 1, wherein said key-actuatable members comprise spring biased pins slidably mounted in said body; said lockrelease elements comprise balls; said pins having elongated bodies with recesses in their sides nestingly to receive and mount said balls; and said recesses providing for motion of the lock-release elements longitudinally of the body relative to said pins. 

1. A locking mechanism characterized by: a body having a longitudinally extending key slot therein; a lock-operating member mounted in the body for movement from a normal position toward a second position which it must occupy before the lock can be released; a plurality of key-actuatable members movably mounted within the body; means urging said key-actuatable members toward positions at which portions thereof are engageable by a key inserted into the key slot, and from which positions said key-actuatable members are movable to predetermine unlocking positions by a proper key in said slot; and lock-release means connected to said key-actuatable members to move therewith, through which key produced motion of said key-actuatable members to their unlocking positions is translated into force on said lock-operating member to effect motion thereof to its said second position; said lock-release means comprising a lock-release element carried by each of said key-actuatable members, said keyactuatable members having a normal lock-closed position in which said lock-release elements are maintained out of operative association with each other, said key-actuatable members in their unlocking positions retaining said lockrelease elements in operative engagement with each other, with each element exerting a force upon the adjacent elements and said force being transmitted to said lock-operating member in a direction to move the latter to its said second position.
 2. A locking mechanism according to claim 1 in which said key-actuatable members comprise spring-biased pins slidably mounted in said body and in which said lock-release elements comprise balls, said pins having elongated pin bodies of various lengths, an upstanding post of reduced diameter on each pin body, and a disc at the free end of each post, said disc and the upper surface of said pin body providing a space in which a baLl is received, each ball being movable longitudinally of the body relative to the pin upon which it is mounted, said balls, in the lock-open position of said pins, forming a linear link for transmitting said force to said lock-operating member.
 3. A pick-proof lock comprising: a cylinder rotatably mounted in a housing; an actuating member movably mounted within said cylinder; means urging said actuating member to a first position in which said lock is closed; a plurality of spring-biased pins slidably mounted in said cylinder; and a lock-release element carried by each of said pins and movable therewith; said pins having a normal lock-closed position in which said lock-release elements are maintained at different levels, said pins being movable, upon insertion of a proper key in said lock, to a lock-open position in which said lock-release elements are located in interengaged relationship to form a linear chain of elements for transmitting a lock-opening force through said cylinder to said actuating member, whereby to move the latter to a second, lock-opening position.
 4. A pick-proof lock according to claim 3 in which said lock-release elements are spherical balls and in which said pins have elongated pin bodies of various lengths, an upstanding post of reduced diameter on each pin body, and a disc at the free end of each post, said disc and the upper surfaace of said pin body providing a space in which a ball is received, each ball being laterally movable relative to the pin upon which it is mounted.
 5. A pick-proof lock according to claim 4 in which said balls are arranged in a chain between said actuating member and a fixed position of said cylinder, said balls being at different levels in the lock-closed position of said pins and the distance between the balls at each end of said chain being insufficient to move said actuating member, said balls being brought into registry in the lock-open position of said pins to form a straight-line chain in which each ball engages the adjacent balls at a point along its diameter to provide a linear chain of greater length, the distance from one end of said linear chain to the other end being sufficient to provide said lock-opening force against said actuating member for moving the latter to its lock-opening position.
 6. A pick-proof lock according to claim 3 in which said actuating member is a lever pivotally mounted within said cylinder.
 7. A pick-proof lock according to claim 5 in which said actuating member is a lever pivotally mounted within said cylinder.
 8. A pick-proof lock according to claim 7 in which said cylinder is freely rotatable in said casing in the locked condition of said lock, and in which a coupling member is journalled in said casing and connected to latch mechanism exteriorly of said lock, said lever having an arm located remote from said coupling member in the first position of said lever, said arm engaging and gripping said coupling member in the second position of said lever, whereby said coupling member is rotatable with said casing to actuate said latch mechanism.
 9. A pick-proof lock according to claim 8 in which said coupling member includes a cylindrical shaft journalled in an end wall of said casing, said shaft having an end slot sized to receive said arm of said lever.
 10. A pick-proof lock according to claim 7 in which said lever has an extension portion projecting from said cylinder and engaging said casing for coupling said cylinder to said casing and restraining rotation of said cylinder, said extension portion moving out of engagement with said casing when said lever is brought to its lock-opening position to release said cylinder for rotational movement within said casing.
 11. A pick-proof lock according to claim 4 in which said pins are arranged in two parallel rows, and in which said balls are mounted on said pins in a direction facing the opposite row, with said balls in alignment along the longitudinal axis of said cylinder.
 12. A picK-proof lock according to claim 11 in which said cylinder has a double keyhole and keyway in alignment with the respective rows of pins.
 13. A locking mechanism according to claim 1, wherein said key-actuatable members comprise spring-biased pins slidably mounted in said body; said lock-release elements comprise balls; said pins having elongated bodies with recesses in their sides nestingly to receive and mount said balls; and said recesses providing for motion of the lock-release elements longitudinally of the body relative to said pins. 